GMC Sierra spins out new trucks capped by the deluxe Denali
Bob Plunkett, Sat, 24 Mar 2007 08:00:00 PDT
GLOBE, Ariz. -- Cruising on U.S. 60 as it cuts through Arizona's Superstition Mountains to the mining capital of Globe, we're riding in the leather-bound driver's bucket of the ultimate plush pickup. It's a full-size rig in half-ton class teaming with the strength of 400 horses as channeled through sophisticated electronic controls to all of the 20-inch chrome-coated wheels.
And the truck's spacious four-door and five-seat passenger compartment is packed with deluxe appointments and equipment which extend to a premium Bose audio package, satellite-linked navigation system, even a backseat DVD video entertainment kit. Call this one the Denali -- a name drawn from native Alaska Athabascan people to describe "the High One" of Mt. McKinley, tallest peak on the North American continent - representing the pinnacle edition for the Sierra 1500 full-size truck by GMC of General Motors.
A humongous 6.2-liter V8 engine mounts beneath that bulging power dome on the hood of Denali and it produces 400 hp at 5700 rpm plus as much as 415 lb-ft of torque at 4400 rpm. Our Denali also gets GM's new heavy-duty Hydra-Matic 6L80 six-speed automatic transmission to handle all of the torque produced by that big V8.
And all power from Denali's V8 is managed through an all-wheel-drive (AWD) system which sends the engine's torque to every wheel for constant traction when running on wet or dry pavement. But there's more: For 2007, the Denali and four other trims of the Sierra 1500 truck earn a bumper-to-bumper makeover based on a new platform from General Motors which delivers best-in-class power, trailer tow ratings and fuel economy scores.
A new platform for the Sierra series has boxed frame rails stretching the length of the vehicle to create a rock-solid and rigid foundation. Also, there's a wider track for front and rear wheels and a lower center of gravity for the structure, which makes this Sierra more stable in motion and, when coupled to a new front suspension mounted on the frame, improves the ride quality and the truck's ability to move through a curvy course without much body roll.
Wheels are bigger now, with the standard size bumped up to 17 inches and options reaching to 20 inches, such as on Denali with 20x8.5 chrome aluminum wheels capped by P275/55R20 AL2 blackwall tires. The suspension is a new coil-over-shock arrangement in front and a Hotchkiss-type live axle at the rear with splayed arrangement of rear axle shock absorbers to improve the ride quality.
Steering is controlled by a rack and pinion mechanism which brings quick and predictable response from the steering wheel. Brakes consist of front discs and rear drums or a disc at each wheel, with linkage to the computerized anti-lock brake system (ABS) and the option of GM's StabiliTrak electronic yaw-controlling anti-skid equipment.
Sierra for 2007 in the 1500 (half-ton) series segments into five different trim designations -- entry-level WT (Work Truck), well-equipped SLE1 and SLE2, deluxe SLT and over-the-top Denali -- with a choice of rear-wheel two-wheel-drive (2WD) traction or the four-wheel-drive (4WD) Autotrak system plus Denali's full-time AWD device.
The intelligent Autotrac active transfer case uses on-board sensors to monitor wheel spin and automatically switch from standard rear-wheel 2WD traction to a 4WD mode which applies the engine's power to front as well as rear wheels. New controls in the Autotrac mechanism induce more torque to the front axle on slick pavement before actual tire slip happens because the device anticipates the tire slippage rather than reacts when it occurs.
There are three different cab styles -- Regular Cab (two doors and a bench or buckets), Extended Cab (bench or buckets in front of a back bench with two wide-swing access doors tucked behind the two front doors), and Crew Cab (a generous four-door cab with front buckets or bench and a back bench broad enough to hold three adults).
There are three different lengths for the rear truck bed -- Short Box (69.3 inches), Standard Box (78.7 inches) and Long Box (97.6 inches). All of the boxes feature two-tier loading with pockets stamped into inner side panels to accept 2x8 planks stretched across the width of the box, as well as built-in bulkhead dividers.
There are five different suspension packages -- Z83, Z85, Z71, Z60 and NHT. These include the Z60 high-performance kit and Z71 off-road package plus one to maximize towing capacity (a Z85 suspension with 46-mm monotube front and rear shock, 9.5-inch rear axle and 17-inch wheels).
And there are lots of powertrains -- an economical six-cylinder plant for Sierra Regular Cab and Extended Cab, plus three different V8s including a FlexFuel version which burns gasoline or E85 ethanol.
The 4.3-liter V6 nets 195 hp at 4600 rpm and 260 lb-ft at 2800 rpm. Vortec V8s begin with a 4.8-liter plant off an iron block with aluminum cylinder heads. It punches out 295 hp at 5600 rpm and torque to 305 lb-ft at 4800 rpm. Sierra shows variations of a 5.3-liter V8 rigged with GM's Active Fuel Management (AFM) technology which cuts by half the number of cylinders engaged in the combustion process when boosted power is not needed in order to conserve fuel.
The 5.3-liter V8 AFM plants make 315 hp at 5200 rpm with 338 lb-ft of torque at 4400 rpm. One version with an iron block offers the FlexFuel capability. And for Sierra Crew Cab, there's a huge V8 geared for trailer tow work. The 6.0-liter V8 muscles up to 367 hp at 5500 rpm and adds top torque numbers of 375 lb-ft at 4300 rpm.
It's strong enough to push the truck's gross vehicle weight rating (GVWR) to 7300 pounds and peg the trailer tow limit at 10500 pounds. The 6.2-liter V8 is exclusive to Denali. GMC presents the Sierra 1500 truck of 2007 in a broad spread of prices -- with MSRP points running from $17,860 for the Sierra Regular Cab WT 2WD to $41,195 for a Sierra Denali AWD.